vfs: Is mounted should be testing mnt_ns for NULL or error.
authorEric W. Biederman <ebiederm@xmission.com>
Mon, 20 Jan 2014 23:26:15 +0000 (15:26 -0800)
committerAl Viro <viro@zeniv.linux.org.uk>
Sun, 26 Jan 2014 13:26:42 +0000 (08:26 -0500)
commit260a459d2e39761fbd39803497205ce1690bc7b1
tree33b18a2cbb1bde334690948c43a107f419be981b
parent9fe55eea7e4b444bafc42fa0000cc2d1d2847275
vfs: Is mounted should be testing mnt_ns for NULL or error.

A bug was introduced with the is_mounted helper function in
commit f7a99c5b7c8bd3d3f533c8b38274e33f3da9096e
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Sat Jun 9 00:59:08 2012 -0400

    get rid of ->mnt_longterm

    it's enough to set ->mnt_ns of internal vfsmounts to something
    distinct from all struct mnt_namespace out there; then we can
    just use the check for ->mnt_ns != NULL in the fast path of
    mntput_no_expire()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The intent was to test if the real_mount(vfsmount)->mnt_ns was
NULL_OR_ERR but the code is actually testing real_mount(vfsmount)
and always returning true.

The result is d_absolute_path returning paths it should be hiding.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/mount.h